Control circuit of transportable crusher

ABSTRACT

A control circuit of a transportable crusher supplies, by the same pump, a required flow rate to hydraulic motors and actuators for a plurality of operating devices having different loads and improves simultaneous operability, fine adjustment, and reproducibility. The control circuit includes at least one variable displacement hydraulic pump (1) for supplying a hydraulic fluid; switch valves (12, 13, 14, 15, 16, 17, 18, 19, 20, 21), for conducting and interrupting the hydraulic fluid from the hydraulic pump (1) to the hydraulic motors and actuators (25a, 26a, 27a, 28a, 29a, 30a, 31a, 32a, 33a, 34a); pressure compensation control valves (11), for inputting front and back pressures of the switch valves, for controlling a discharge flow rate of the hydraulic pump (1) so that the difference of the front and back pressures can become constant and for distributing the discharge flow rate in accordance with a required power of the respective hydraulic motors and actuators or in accordance with a predetermined priority when the switch valves are simultaneously operated; and a controller (41), for controlling the switch valves to a predetermined value set in accordance with the load of the hydraulic motors and actuators.

TECHNICAL FIELD

The present invention relates to a control circuit of a transportablecrusher and more specifically to a control circuit of a transportablecrusher which can perform an optimum hydraulic drive.

BACKGROUND ART

Heretofore, as this type of control circuit of transportable crusher,there has been proposed the control circuit of the transportable crushershown in FIG. 14 (see Japanese Utility Model Laid-open No.6-81641/1994).

In FIG. 14, a variable displacement left-side traveling hydraulic pump101, a variable displacement right-side traveling hydraulic pump 102,and a fixed displacement controlling hydraulic pump 103 are driven by anengine (not shown) mounted in the transportable crusher.

A hydraulic fluid discharged from the left-side traveling hydraulic pump101 flows into a P port of a left-side traveling switching control valve104 (hereinafter, referred to as left-side control valve 104). Thishydraulic fluid is supplied to a hydraulic motor 105 in a hydraulicallydrivable type forwardly reversely rotatable left-side traveling truckconnected to an A port and a B port of the left-side control valve 104.

The hydraulic fluid discharged from the right-side traveling hydraulicpump 102 flows into the P port of a right-side traveling switchingcontrol valve 106 (hereinafter, referred to as a right-side controlvalve 106). This hydraulic fluid is supplied to a hydraulic motor 107 ina hydraulically drivable type forwardly reversely rotatable right-sidetraveling truck connected to the A port and the B port of the right-sidecontrol valve 106.

When the left-side control valve 104 is positioned at its neutralposition S, the left-side control valve 104 is "an open-center typesix-port and three-position pilot hydraulic control valve" which iscommunicated with the P port and an N port so as to bypass a flow. Theleft-side control valve 104 and the right-side control valve 106 havethe same structure.

When each of the left-side control valve 104 and the right-side controlvalve 106 is positioned at its neutral position S, the hydraulic fluiddischarged from the left-side traveling hydraulic pump 101 and thehydraulic fluid discharged from the right-side traveling hydraulic pump102 flow out of the N ports. After that time, the hydraulic fluids arejoined to each other and flow into the P port of a hydraulic controlvalve 108 for the crusher. This hydraulic fluid is supplied to ahydraulic motor 109 for the crusher connected to the A port and the Bport of the hydraulic control valve 108 for the crusher. Two reliefvalves 110, 110 for the crusher are arranged in this control circuit insuch a manner that a supplied hydraulic pressure is not a predeterminedvalue or higher during a forward-and-reverse rotation of the hydraulicmotor 109 for the crusher.

The hydraulic control valve 108 for the crusher also has the samestructure as the left-side control valve 104 and the right-side controlvalve 106. When the hydraulic control valve 108 for the crusher ispositioned at its neutral position S, its P port and its N port arecommunicated with each other so as to drain the hydraulic fluid into atank 123.

When the left-side control valve 104 and the right-side control valve106 are switching-controlled to their first switching position F so thatthe respective P port is communicated with the respective A port, theleft-side hydraulic motor 105 and the right-side hydraulic motor 107 arerotated forwardly. On the other hand, when the left-side control valve104 and the right-side control valve 106 are switching-controlled totheir second switching position R so that the respective P port iscommunicated with the respective B port, the left-side hydraulic motor105 and the right-side hydraulic motor 107 are rotated in reverse.

When the left-side hydraulic motor 105 and the right-side hydraulicmotor 107 are driven, that is, when the hydraulic pressure from therespective P port is supplied to either the respective A port or therespective B port in the left-side control valve 104 and the right-sidecontrol valve 106, the respective N port for supplying the hydraulicpressure to the hydraulic control valve 108 for the crusher is alwaysblocked. Thus, the hydraulic motor 109 for the crusher is not driven.

On the other hand, when the left-side control valve 104 and theright-side control valve 106 are positioned at their respective neutralposition S, hydraulic pressure is supplied from the respective N port.The hydraulic motor 109 for the crusher is driven in accordance with thethus joined hydraulic pressure.

The controlling hydraulic pump 103 supplies hydraulic pressure to acontrol hydraulic line 111 which is connected to the left-side controlvalve 104, the right-side control valve 106, and the hydraulic controlvalve 108 for the crusher. The controlling hydraulic pump 103 alsosupplies the hydraulic pressure to hydraulic lines 112, 113, and 114,which are connected to the hydraulic motors for attached devices, suchas a discharge conveyor, a magnetic separator, and a conveyor derrickingdevice, by a shunt circuit 115.

The shunt circuit 115 is shunted into two systems by a first priorityvalve 116 on the discharge side of the controlling hydraulic pump 103.One outlet side port of the first priority valve 116 is connected to thehydraulic line 112, which is connected to the hydraulic motor for thedischarge conveyor and to a first relief valve 117. The other outletside port of the first priority valve 116 is connected to an inlet sideport of a second priority valve 118.

Similarly, the outlet side port of the second priority valve 118 isconnected to the hydraulic line 113 which is connected to the hydraulicmotor for the magnetic separator and to a second relief valve 119. Theother outlet side port of the second priority valve 118 is connected tothe inlet side port of a third priority valve 120.

In a last step, one outlet side port of the third priority valve 120 isconnected to the hydraulic line 114, which is connected to the hydraulicmotor for the conveyor derricking device and to a third relief valve121. The other outlet side port of the third priority valve 120 is heldto a predetermined control pressure by a relief valve 122 for thecontrol hydraulic line and is connected to the control hydraulic line111.

Each hydraulic motor for these attached devices is connected so that themotor requiring the higher hydraulic pressure during an operation can belocated in a previous step. The first, second, and third priority valves116, 118, and 120 are constructed so that they can be shunted at a flowrate distribution ratio of as high as, for example, one to ten. Thefirst, second, and third priority valves 116, 118, and 120 are arrangedin accordance with the number of hydraulic motors.

A joined discharge flow rate from the left-side traveling hydraulic pump101 and the right-side traveling hydraulic pump 102 is supplied to thehydraulic motor 109 for the crusher so that the speed may not be reducedif the load and a load variation become larger.

The hydraulic motors for the discharge conveyor, for the magneticseparator, and for the conveyor derricking device have less displacementand less load variation than the hydraulic motor 109 for the crusher.However, the controlling hydraulic pump 103 for the control hydraulicline 111 and for the hydraulic lines 112, 113, and 114 for the attacheddevices is a fixed displacement type having a large pump displacement.The controlling hydraulic pump 103 includes the shunt circuit 115 whichshunts the excess discharge flow rate. The controlling hydraulic pump103 is used through the priority valves 116, 118, and 120 of the shuntcircuit 115.

Accordingly, the two variable displacement traveling hydraulic pumps 101and 102, for use with the hydraulic motor 109 for the crusher, and thesingle fixed displacement controlling hydraulic pump 103, for use withboth the control hydraulic line 111 and the attached devices, have noinfluence on each other, even if the loads of both the pumps are varied.Thus, they can be independently driven.

FIG. 15 shows an example of a prior-art speed control circuit of ahydraulic motor 124 for a feeder. This speed control circuit controls aspeed of the hydraulic motor 124 for the feeder in order to select anintroduction speed of objects to be crushed in accordance with the sizeand hardness of the objects to be crushed and the kind of crusher usedfor crushing the objects.

A speed control of the hydraulic motor 124 for the feeder isaccomplished by a bleed-off circuit in which a flow rate regulatingvalve 125 is inserted between the discharge side of the hydraulic pump103 and a tank 123. A discharge flow rate Qp of the hydraulic pump 103is divided into a flow rate Q_(M) to be supplied to the hydraulic motor124 for the feeder and a flow rate Q_(T) to be shunted to the tank 123.The excess flow rate Q_(T) is regulated by the flow rate regulatingvalve 125. The flow rate Q_(M), alone required for the hydraulic motor124 for the feeder, is supplied through a switching control valve 126for the feeder.

On the other hand, the conventional control circuit of the transportablecrusher includes the two variable displacement traveling hydraulic pumps101 and 102. The reason is as follows. When the load of the left-sidehydraulic motor 105 is different from that of the right-side hydraulicmotor 107, even if the left-side control valve 104 and the right-sidecontrol valve 106 have the same stroke, the hydraulic fluid flows intothe hydraulic motor having the lower load. Therefore, since the speed ofthe hydraulic motor having the higher load becomes lower, thetransportable crusher cannot travel in a straight line. Thus, the twotraveling hydraulic pumps 101 and 102 are disposed so as to ensurestraight traveling. However, this complicates the piping system and thecontrol system, and a maintenance check takes a long time, therebyresulting in a high cost.

The left-side control valve 104 and the right-side control valve 106 arethe open-center type in which the respective P port and the respective Nport are communicated with each other at the neutral position S. Thus,during each half stroke, the hydraulic fluid, set to a predeterminedpressure at the P port, is partially drained into the tank 123 via the Pport and the N port of the hydraulic control valve 108 for the crusher.If a drain flow rate is high, a power loss of the traveling hydraulicpumps 101 and 102 is caused. If the drain flow rate remains high for along time, the hydraulic fluid is heated, thereby causing an overheatingof the hydraulic circuit. In such a manner, a problem is caused.

When the single fixed displacement controlling hydraulic pump 103, foruse in both the control hydraulic line 111 and the hydraulic lines 112,113, and 114 for the attached devices, is installed, a large pumpdisplacement is required for the total flow rate necessary for theselines.

For example, with regard to the crusher broadly illustrated in FIG. 3,the controlling hydraulic pump 103, having a larger pump displacement,is also required in order to supply the hydraulic fluid to eachhydraulically drivable type motor for a feeder 29 for stably supplyingthe objects to be crushed which are introduced into the hopper forcrusher 28, a vibrating screen 32, a plurality of secondary conveyors 33and 34, etc.

In addition, the shunt circuit 115, having a different predetermined setpressure, is disposed on the discharge side of the controlling hydraulicpump 103. As the number of attached devices is increased as describedabove, the priority valve and the relief valve for the control hydraulicline, to be mounted to each hydraulic line, must be increased. As aresult, the drain flow rate is further increased, thereby resulting infurther power loss of the controlling hydraulic pump 103. Since thehydraulic fluid is heated, the hydraulic circuit can become overheated.Since the piping system and the control system are complicated, themaintenance check takes a long time.

Furthermore, assume that the discharge conveyor is overloaded, that is,the objects to be crushed are discharged over a predetermined throughputcapacity of the discharge conveyor. At that time, the first relief valve117, of the hydraulic line 112 connected to the hydraulic motor for thedischarge conveyor, is relieved; and thereby the hydraulic motor 109 forthe crusher and the feeder are automatically stopped. Although anoperator can restart the motor and the feeder after a check of thefailure, this is troublesome.

The speed control circuit of the hydraulic motor 124 for the feedershown in FIG. 15 selects the flow rate Q_(M) required for the hydraulicmotor 124 for the feeder by the flow rate regulating valve 125 andregulates the flow rate Q_(T) to be shunted to the tank 123. However,when the load and an oil temperature of the hydraulic fluid are variedin accordance with the amount of the objects, to be crushed, on thefeeder, the flow rate Q_(M) is changed and thereby the speed of thehydraulic motor 124 for the feeder is also changed. Disadvantageously,the reduction of the speed of the hydraulic motor 124 for the feederresults in a reduction of crushing efficiency.

According to the circumstances of the load and the oil temperature ofthe hydraulic fluid, the crusher can be abnormally overloaded. Thus, theobjects to be crushed jam the crusher, thereby resulting in an emergencystop. Immediately before the abnormal overload, it is difficult for theoperator to regulate the flow rate regulating valve 125. It is also verydifficult to remote-control the flow rate regulating valve 125, which isincorporated in the structure of the switching control valve 126 for thefeeder.

Even if the load of the hydraulic motor 124 for the feeder is reduced,the jammed objects to be crushed must be removed from the crusher in anemergency-stop status. Therefore, since an automatic restoration isdifficult, the operating efficiency of the transportable crusher isreduced.

SUMMARY OF THE INVENTION

The present invention is accomplished in view of such problems of theprior art. It is a first object of the present invention to provide acontrol circuit of a transportable crusher which supplies, by the samepump, a required flow rate to hydraulic motors and actuators for aplurality of operating devices having different loads, and improvessimultaneous operability, fine adjustment, and reproducibility. It is asecond object of the present invention to provide a control circuit of atransportable crusher which prevents an overload of each device bysetting an order of priority of operation/stop for a plurality ofoperating devices and has safety during the traveling of thetransportable crusher.

The present invention provides a control circuit of a transportablecrusher having hydraulic units for a plurality of operating deviceshaving different loads, for crushing objects to be crushed by thecrusher, wherein each hydraulic unit is either a hydraulic motor or anactuator, the control circuit comprising at least one variabledisplacement hydraulic pump for supplying a hydraulic fluid, switchvalves for conducting and interrupting the hydraulic fluid from thehydraulic pump to the hydraulic units, pressure compensation controlvalves for inputting front and back pressures of the switch valves, forcontrolling a discharge flow rate of the hydraulic pump so that thedifference of the front and back pressures can become constant, and fordistributing the discharge flow rate in accordance with the powerrequired by the respective hydraulic units or in accordance with apredetermined priority when the switch valves are simultaneouslyoperated, and control means for controlling the switch valves to apredetermined value set in accordance with the load of the hydraulicunits.

A spool of a feeder valve, for controlling a speed of a feeder which isone of the plurality of operating devices, includes, in one part of atapered notch portion for flowing a predetermined flow rate proportionalto an opening area of the spool in accordance with a flow rate requiredby a hydraulic motor for the feeder, a parallel notch portion which isparallel to the spool outer circumference for allowing the flow rate tobe constant even if the amount of movement of the spool is increased.

In the control circuit, the control means comprises comparators forcomparing signals, inputted from detecting means for detecting the loadof the hydraulic motors for driving the plurality of operating devices,to an equivalent load level to which a setter presets the load of thefeeder, and an output circuit for outputting an instruction signal to asolenoid proportional reducing valve of the feeder in response to outputsignals of the comparators and for controlling the speed of the feeder.

In the control circuit, the control means comprises a current pattern Aof a first speed control for starting, accelerating/decelerating, andstopping the hydraulic motor of the feeder, and a current pattern B of asecond speed control for starting, accelerating/decelerating, andoperating at a set value speed, and an instruction is given to thesolenoid proportional reducing valve in accordance with one of thecurrent patterns selected by an identification switch so as to controlthe speed of the feeder.

In the control circuit, a discharge conveyor, which is one of theplurality of operating devices, comprises a position sensor, fordetecting a storing position, connected to the control means through apower source circuit. The position sensor is turned OFF when thedischarge conveyor is positioned at a lower position during a crushingoperation, and a signal from the control means to a traveling interlocksolenoid valve of the transportable crusher is turned OFF so that thetraveling of the transportable crusher is prevented.

The position sensor is connected to a rotating light and an alarm fordisplaying the traveling of the transportable crusher, and the positionsensor is turned ON when the discharge conveyor is positioned at anupper position during a stop of the operation so that the rotating lightand the alarm are actuated.

In such a construction, the discharge flow rate of the single hydraulicpump is supplied in parallel to the hydraulic motors and actuators for aplurality of operating devices having different loads. This hydraulicpump includes the pressure compensation control valves for inputting thefront and back pressures of the closed-center type switch valves, whichindividually control the hydraulic fluid to the hydraulic motors andactuators, and for controlling the discharge flow rate of the pump sothat these front and back pressures can become constant.

Regardless of the size of the load of each hydraulic motor and actuator,each switch valve distributes the discharge flow rate of the hydraulicpump into each hydraulic motor and actuator in accordance with theopening area of the respective switch valve. Therefore, the drivingspeed of the large displacement hydraulic motor for the crusher isactuated at a predetermined speed, even if the load of the largedisplacement hydraulic motor is varied. The driving speed of the motorfor the feeder, the discharge conveyor, etc., is also actuated at apredetermined speed in the same manner.

As a result, the crusher crushes the objects to be crushed, at aconstant speed and delivers the crushed objects to the dischargeconveyor. Therefore, fewer emergency stops are caused, due to theoverload of the crusher and the discharge conveyor, without reducingcrushing efficiency.

The hydraulic pump is not specifically divided into one for the crusherand others for other operating devices. The variable displacementhydraulic pump having a single discharge flow rate can be disposed inaccordance with the total required power. Accordingly, the singlehydraulic pump is controlled so as to minimize the flow rate of thepressurized oil to be relieved from a relief valve to a tank in order tohold the pressure. Therefore, a heat generation of the hydraulic fluidin the tank is reduced.

Each switch valve and each pressure compensation valve connected to eachhydraulic motor and each actuator control the flow rate whichdistributes the discharge flow rate of the hydraulic pump into eachhydraulic motor and each actuator. Thus, while the objects to becrushed, which are introduced into the hopper, are crushed by thecrusher, the hydraulic motor of any one of the feeder, the crusher, orthe discharge conveyor can be overloaded. At that time, the dischargeflow rate of the pump is distributed, for example, in the order of thecrusher, the discharge conveyor, and the feeder in accordance with apredetermined priority.

The control of the switch valves is effected by the solenoidproportional reducing valves and the solenoid valves. In order tocontrol the valves in the order of priority, the control means firstinstructs the solenoid proportional reducing valve for the feeder tostop the feeder so as to stop feeding the objects to be crushed, to thecrusher. Next, the control means instructs the solenoid valve for thedischarge conveyor to stop the discharge conveyor after a predeterminedtime interval so as to stop the discharge conveyor. Within apredetermined time interval, the crusher crushes the objects to becrushed in the crusher, and then discharges the crushed objects to thedischarge conveyor. Finally, the control means gives the instruction tostop the crusher so as to stop the crusher. Accordingly, the crushedobjects are not jammed into the crusher and do not remain on thedischarge conveyor. Therefore, even if each hydraulic motor isoverloaded, an action is performed so that the load can be sequentiallyreduced. Thus, the control circuit is easy to automatically restore,thereby improving the crushing efficiency. Since the crushed objects inthe crusher and on the discharge conveyor are discharged, a check andmaintenance work of the crusher and the discharge conveyor is alsofacilitated.

The spool of the feeder valve for controlling the speed of the feederincludes, in one part of the tapered notch for flowing a predeterminedflow rate proportional to the opening area of the spool in accordancewith a required flow rate of the hydraulic motor for the feeder, theparallel notch portion, which is parallel to the spool outercircumference. Thus, when the feeder valve is operated, there is formeda portion where the flow rate becomes constant even if the opening areaof the feeder valve is increased, that is, the portion where the speedbecomes constant in a status of the speed of set value. The portionhaving the speed of set value is set so that the feeder valve can beeasily operated in speed stages of rated speed and set value speed.Thus, a fine rotation control becomes possible during the high load ofthe feeder. By adjusting the grit of the crushed objects, the grit ofproduct desired by a user can be ensured.

The control means outputs an instruction to the solenoid proportionalreducing valve inserted in a pilot circuit of the feeder valve. Thecontrol means compares each signal, inputted from each detecting meansfor detecting the load of each hydraulic motor for driving a pluralityof operating devices, to the equivalent load level to which the setterpresets the load of the feeder. The instruction signal is outputted tothe solenoid proportional reducing valve of the feeder from the outputcircuit in response to the outputted signal. The feeder is started,accelerated/decelerated, operated at the set value speed, or stopped.

The control means also comprises the current pattern A of the firstspeed control for starting, accelerating/decelerating, and stopping thehydraulic motor of the feeder and the current pattern B of the secondspeed control for starting, accelerating/decelerating, and operating atthe set value speed. The identification switch can select either currentpattern. The current pattern A of the first speed control can be usedfor a plate feeder. The current patter B of the second speed control canbe used for a vibrating feeder having a resonant point at a low speedjust before the stop. When the current pattern B of the second speedcontrol is used for the vibrating feeder, the vibrating feeder isoperated at the set value speed prior to resonating. After the reductionof the load of the crusher and the discharge conveyor, an automaticrestoration for accelerating the vibrating feeder up to the rated speedis facilitated. The crushing efficiency is improved. Furthermore, evenif the hydraulic motors for the plate feeder and for the vibratingfeeder have different performances, the common hydraulic pump and theswitch valves can be used.

When the discharge conveyor is positioned at the lower position duringthe operation, the position sensor is turned OFF. The signal from thecontrol means to the traveling interlock solenoid valve of thetransportable crusher is turned OFF. The transportable crusher cannottravel. Therefore, if the operator should inadvertently press atraveling lever during the crushing operation, the transportable crusherdoes not travel, thereby allowing the safety to be ensured.

When the discharge conveyor is positioned at the upper position duringthe stop of the crushing operation, the position sensor is turned ON.The rotating light and the alarm are actuated so as to display thetraveling of the transportable crusher.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a hydraulic circuit diagram of a control circuit of atransportable crusher according to an embodiment of the presentinvention;

FIG. 2 is a block diagram of a controller for the control circuit shownin FIG. 1; FIG. 3 is a side view of a transportable crusher mounting thecontrol circuit and the controller shown in FIGS. 1 and 2;

FIG. 4 is an illustration of an opening/closing valve of a crusher case;

FIG. 5 is an illustration of right and left traveling valves;

FIG. 6 is an illustration of a crusher valve;

FIG. 7 is an illustration of a feeder valve;

FIG. 8 is a cross sectional view of the feeder valve shown in FIG. 7;

FIG. 9A is a partially enlarged view of FIG. 8;

FIG. 9B is an illustration showing characteristics of flow rate relativeto an amount of movement of a spool of the feeder valve;

FIG. 10 is a circuit diagram showing an overload preventing circuit inthe controller shown in FIG. 2;

FIG. 11 is a flow chart of a traveling interlock circuit of a dischargeconveyor;

FIG. 12 is an illustration showing characteristics of flow rate relativeto a current value of the feeder valve;

FIGS. 13A and 13B are graphs representing instruction tables classifiedby two kinds of feeders;

FIG. 14 is a control circuit diagram of a transportable crusher of theprior art; and FIG. 15 is a speed control circuit diagram of a hydraulicmotor for the feeder of the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of a control circuit of a transportable crusher accordingto the present invention will be described in detail with reference toFIGS. 1 through 13B.

As shown in FIG. 1, a variable displacement hydraulic pump 1 and a fixeddisplacement controlling hydraulic pump 2 are driven together by anengine 3, which is mounted to the transportable crusher. The hydraulicpump 1 includes a TVC (Torque Variable Control) valve 4, an LS (LoadSensing) valve 5, and a servo piston 6.

The TVC valve 4 is a three-port and two-position proportional flow ratecontrol valve. The TVC valve 4 controls an angle of an inclined plate ofthe hydraulic pump 1 by the servo piston 6 so that a pump absorbingtorque can be maintained to the extent that the engine 3 is not stopped.That is, when a pump discharge hydraulic pressure Pp is increased, theamount of discharge Qp of the hydraulic pump 1 is reduced. On the otherhand, when the pump discharge hydraulic pressure Pp is reduced, theamount of discharge Qp is increased.

The LS valve 5 is a three-port and two-position proportional flow ratecontrol valve. The LS valve 5 is controlled by the discharge hydraulicpressure Pp of the hydraulic pump 1 and an LS pressure PLS, which isgenerated in a load pressure circuit LS12 of each hydraulic motorconnected to an outlet port LS11 of each pressure compensation valve 11in an operating valve assembly 8. The LS valve 5 is balanced by thedischarge hydraulic pressure Pp and the LS pressure PLS so that an LSdifferential pressure can be always constant. When the LS differentialpressure is lower than a set pressure of the LS valve 5, the LS valve 5actuates the servo piston 6 so as to increase the angle of the inclinedplate, thereby increasing the amount of pump discharge Qp. On thecontrary, when the LS differential pressure is higher than the setpressure of the LS valve 5, the LS valve 5 reduces the angle of theinclined plate, thereby reducing the amount of pump discharge Qp.

The servo piston 6 sets a reference pressure to the discharge hydraulicpressure Pp and sets a control pressure to the LS differential pressure.The angle of the inclined plate of the hydraulic pump 1 is variablyactuated so as to vary the amount of pump discharge Qp.

On a discharge side of the hydraulic pump 1 is disposed the stack-shapedoperating valve assembly 8 which switching-controls a flow ratedistribution and a direction of flow of hydraulic pressure from thehydraulic pump 1 through an oil path 7 and can increase/reduce thenumber of units so that number can be the necessary number for theswitching control. The oil path 7 is connected to each of a plurality ofinlet ports 11P disposed in the operating valve assembly 8.

The operating valve assembly 8 comprises, besides the pressurecompensation valves 11, closed-center type switch valves such as anunload valve 9 and a relief valve 10 for controlling the pressure, acrusher case opening/closing valve 12, a left traveling valve 13, aright traveling valve 14, a crusher valve 15, a feeder valve 16, adischarge conveyor valve 17, a magnetic separator valve 18, a vibratingscreen valve 19, a secondary loading conveyor valve 20, and a secondarystock conveyor valve 21. On the inlet sides of the switch valves aredisposed the pressure compensation valves 11, which are connected inparallel to the oil path 7 and balance one load pressure with anotherload pressure.

The valves described below are connected in parallel through a pilot oilpath P7 on the discharge side of the controlling hydraulic pump 2. Thatis, a case opening/closing PPC valve (direct acting proportionalreducing valve) P12 is connected so as to pilot-operate the crusher caseopening/closing valve 12. An EPC valve (solenoid proportional reducingvalve) P15a, for forwardly rotating the crusher and an EPC valve 15b,for reversely rotating the crusher, are connected so as to pilot-operatethe crusher valve 15. An EPC valve P16a, for forwardly rotating thefeeder, and an EPC valve 16b, for reversely rotating the feeder, areconnected so as to pilot-operate the feeder valve 16.

The controlling hydraulic pump 2 discharges an amount of discharge Qpa.A relief valve P10 is disposed on the discharge side of the controllinghydraulic pump 2.

To the pilot oil path P7 are similarly connected in parallel athree-port and two-position traveling interlock solenoid valve P8, adischarge conveyor rotating solenoid valve P17 for pilot-operating thedischarge conveyor valve 17, a magnetic separator solenoid valve P18 forpilot-operating the magnetic separator valve 18, a screen solenoid valveP19 for pilot-operating the vibrating screen valve 19, a loadingconveyor solenoid valve P20 for pilot-operating the secondary loadingconveyor valve 20, and a stock conveyor solenoid valve P21 forpilot-operating the secondary stock conveyor valve 21.

A left traveling PPC valve P13, for pilot-operating the left travelingvalve 13, and a right traveling PPC valve P14, for pilot-operating theright traveling valve 14, are connected in parallel through a pilot oilpath P9 to the outlet port of the traveling interlock solenoid valve P8,which is switched by a signal P8e.

To the control ports A1 and B2 of the crusher case opening/closing valve12 is connected an actuator 25a for opening/closing the crusher case 25when the crusher 28 is set up. A port O of the case opening/closing PPCvalve P12 is connected to a hydraulic port PA1 of the crusher caseopening/closing valve 12. A port C of the case opening/closing PPC valveP12 is connected to a hydraulic port PB1 of the crusher caseopening/closing valve 12 in a similar manner.

To the control ports A1 and B2 of the left traveling valve 13 isconnected a hydraulic motor 26a in a hydraulically drivable typeforwardly reversely rotatable left-side traveling truck 26. A port F ofthe left traveling PPC valve P13 is connected to the hydraulic port PA1of the left traveling valve 13. A port R of the left traveling PPC valveP13 is connected to the hydraulic port PB1 of the left traveling valve13 in a similar manner.

To the control ports A1, B2 of the right traveling valve 14 is connecteda hydraulic motor 27a in a hydraulically drivable type forwardlyreversely rotatable right-side traveling truck 27. The port F of theright traveling PPC valve P14 is connected to the hydraulic port PA1 ofthe right traveling valve 14. The port R of the right traveling PPCvalve 14 is connected to the hydraulic port PB1 of the right travelingvalve 14 in a similar manner.

To the control ports A1 and B2 of the crusher valve 15 are connected aforwardly reversely rotatable hydraulic motor 28a, for operating thecrusher 28 to crush objects to be crushed, and a sensor LS15, fordetecting the load pressure of the hydraulic motor 28a.

The hydraulic port PA1 of the crusher valve 15 is connected to theoutlet port of the EPC valve P15a, which is controlled by a proportionalcurrent of a signal P15ae, for forwardly rotating the crusher. Thehydraulic port PB1 of the crusher valve 15 is similarly connected to theoutlet port of the EPC valve P15b, which is controlled by theproportional current of a signal P15be, for reversely rotating thecrusher.

To the control ports A1 and B2 of the feeder valve 16 are connected aforwardly reversely rotatable hydraulic motor 29a, for the feeder 29 fordelivering a fixed quantity of objects to be crushed from the hopper 35to the crusher 28, and the sensors LS16F and LS16R, for detecting theload pressure of the hydraulic motor 29a.

The hydraulic port PA1 of the feeder valve 16 is connected to the outletport of the EPC valve P16a, which is controlled by the proportionalcurrent of a signal P16ae, for forwardly rotating the feeder. Thehydraulic port PB1 of the feeder valve 16 is also connected to theoutlet port of the EPC valve P16b, which is controlled by theproportional current of a signal P16be, for reversely rotating thefeeder.

To the control ports A1 and B2 of the discharge conveyor valve 17 areconnected a hydraulic motor 30a, for rotating a discharge conveyor 30 todischarge the objects crushed by the crusher 28, and a sensor LS17, fordetecting the load pressure of the hydraulic motor 30a. The hydraulicport PA1 of the discharge conveyor valve 17 is connected to a tank 22.The hydraulic port PB1 of the discharge conveyor valve 17 is alsoconnected to the outlet port of the discharge conveyor rotating solenoidvalve P17, which is switched by a signal P17e.

To the control ports A1 and B2 of the magnetic separator valve 18 areconnected a hydraulic motor 31a for rotating a magnetic separator 31,for separating magnetic metal pieces such as an iron mixed in thecrushed objects on the discharge conveyor 30, and a sensor LS18, fordetecting the load pressure of the hydraulic motor 31a. The hydraulicport PA1 of the magnetic separator valve 18 is also connected to thetank 22. The hydraulic port PB1 of the magnetic separator valve 18 isalso connected the outlet port of the magnetic separator solenoid valveP18, which is switched by a signal P18e.

To the control ports A1 and B2 of the vibrating screen valve 19 areconnected a hydraulic motor 32a, for rotating a vibrating screen 32, anda sensor LS19, for detecting the load pressure of the hydraulic motor32a. The hydraulic port PA1 of the vibrating screen valve 19 isconnected to the tank 22. The hydraulic port PB1 of the vibrating screenvalve 19 is also connected to the outlet port of the screen solenoidvalve P19, which is switched by a signal P19e.

To the control ports A1 and B2 of the secondary loading conveyor valve20 are connected a hydraulic motor 33a, for rotating a secondary loadingconveyor 33, and a sensor LS20, for detecting the load pressure of thehydraulic motor 33a. The hydraulic port PA1 of the secondary loadingconveyor valve 20 is connected to the tank 22. The hydraulic port PB1 ofthe secondary loading conveyor valve 20 is connected to the outlet portof the loading conveyor solenoid valve P20, which is switched by asignal P20e.

To the control ports A1 and B2 of the secondary stock conveyor valve 21are connected a hydraulic motor 34a, for rotating a secondary stockconveyor 34, and a sensor LS21, for detecting the load pressure of thehydraulic motor 34a. The hydraulic port PA1 of the secondary stockconveyor valve 21 is connected to the tank 22. The hydraulic port PB1 ofthe secondary stock conveyor valve 21 is connected to the outlet port ofthe stock conveyor solenoid valve P21, which is switched by a signalP21e.

The unload valve 9 is a valve for relieving the amount of discharge Qp,corresponding to the minimum angle of the inclined plate of thehydraulic pump 1, into the tank 22 at an unload pressure Pap when eachswitch valve constituting the operating valve assembly 8 is positionedat a neutral position. The unload valve 9 is constructed so that theaforementioned LS pressure PLS can act upon a vent circuit of the unloadvalve 9. During a fine operation of each switch valve, the unload valve9 relieves one part of the amount of discharge Qp of the hydraulic pump1 into the tank 22. The discharge hydraulic pressure Pp is increased upto the pressure which is equal to the unload pressure Pap plus the LSpressure PLS.

The relief valve 10 is a safety valve for relieving the amount ofdischarge Qp into the tank 22 and for reducing to a predeterminedpressure when the discharge oil path 7 of the hydraulic pump 1 isincreased to a predetermined pressure or higher. The relief valve P10 isthe safety valve for relieving the amount of discharge Qpa into the tank22 and for reducing to a predetermined pressure when the discharge oilpath P7 of the hydraulic pump 2 is increased to a predetermined pressureor higher.

As shown in FIG. 2, to a mounted battery 40 are connected a controller41, which is a control means, and a limit switch 43, which is one of theposition sensors. During the operation of the discharge conveyor 30, thedischarge conveyor 30 is positioned at a lower position 42a about afulcrum of a pivot pin 42. Therefore, the limit switch 43 is turned OFFso as to disconnect a power source circuit 44.

At this time, the power source circuit 44 inputs a signal to thecontroller 41 so that the output signal P8e of the controller 41 isturned OFF. The pilot oil path P9, connected to the traveling interlocksolenoid valve P8, communicates with the tank 22. If either the lefttraveling PPC valve P13 or the right traveling PPC valve P14 isoperated, the interlock is carried out so that the transportable crushercan not travel.

A rotating light 45 and an alarm 46 are connected to the power sourcecircuit 44. During the traveling of the transportable crusher, thedischarge conveyor 30 is positioned at an upper position 42b about thefulcrum of the pivot pin 42. Therefore, the limit switch 43 is turned ONso as to connect the power source circuit 44. The rotating light 45 andthe alarm 46 are actuated.

As shown in FIG. 3, the controller 41 is divided into a main controller41a and a remote controller 41b, which can remote-control a workingmachine.

As shown in FIGS. 2 and 3, signals are inputted to the controller 41from the feeder switches 47 and 48, which can manually turn ON/OFF thefeeder 29; a speed setter 49, which can set the speed of the feeder 29;and a feeder identification switch 56. The feeder identification switch56 is for identifying a plate feeder and a grizzly vibrating feeder inthe feeder 29 and for inputting the signal, where the grizzly vibratingfeeder vibrates a grizzly bar so as to discharge the objects to becrushed finer than the grit of the grizzly bar before the introductioninto the crusher 28.

Signals are also inputted to the controller 41 from the sensors LS15,LS16F, LS16R, LS17, LS18, LS19, LS20, and LS21, which are detectingmeans for detecting the load of the respective hydraulic motor. Thesignals P8e, P15ae, P15be, P16ae, P16be, P17e, P18e, P19e, P20e and P21eare then outputted.

In FIG. 4, the pressure compensation valve 11 is a composite valve inwhich a flow rate regulating valve 11a is coupled to a reducing valve11b. The differential pressure becomes constant in a flow rate controlmechanism PQ between the inlet pump port P and the outlet control portA1 or B2 of the crusher case opening/closing valve 12. At that time,even if the pressure compensation valve 11 is operated together withother switch valves, it acts so that the differential pressure canbecome the same.

The pressure compensation valve 11 puts the hydraulic pressure Pp intoan inlet port 7a through a throttle 11e. The reducing valve 11b is usedso as to reduce to the same pressure as a load pressure PLP of theactuator 25a. The top pressure is fetched at the outlet of the operatingvalve assembly 8 through a check valve 11c so that the top pressure isdefined as the LS pressure PLS.

The crusher case opening/closing valve 12 is a closed-center type ofeight-port and three-position spring center pilot operated type switchvalve. The eight ports include a pump port P, connected to the outlet ofthe flow rate regulating valve 11a as the inlet port; a pilot port P1,of the load pressure PLP for controlling the reducing valve 11b to theLS pressure PLS; and two tank ports T1 and T2. The control ports A1 andA2 and the control ports B1 and B2 are disposed as the outlet ports. Theoil path of the control port A2 is coupled to that of the control portB1. The two tank ports T1 and T2 are connected to the tank 22.

The three positions include a neutral position S1 of a spring centerhaving "P1, B1 connection" and other ports closed; a case openingposition 01, having "P, B1 connection with the flow rate controlmechanism PQ", "B2, T2 connection", "B1, P1 connection", "A2, A1connection" and T1 closed; and a case closing position C1, having "P, A2connection with the flow rate control mechanism PQ", "B1, B2, P1connection", "A1, T1 connection", and T2 closed.

Hydraulic chambers PA1 and PB1, for pilot-operating the case openingposition 01 and the case closing position C1, and springs are disposedat both ends of the crusher case opening/closing valve 12.

In FIG. 5, the pressure compensation valve 11 has the same structure asin FIG. 4. Since the same components have the same reference numbers,the description is omitted.

The neutral position S1 of the left traveling valve 13 and the righttraveling valve 14 has "A1, T1 connection", "B2, T2 connection", "P1, B1connection", and P, A2 closed. The oil path of the control port A2 iscoupled to that of the control port B1. The two tank ports T1 and T2 areconnected to the tank 22. The connection position of each port of otheradvance position F2 and back position R2 is the same as the case openingposition 01 and the case closing position C1. Thus, the description isomitted.

In FIG. 6, the pressure compensation valve 11 has the same structure asin FIG. 4. Since the same components have the same reference numbers,the description is omitted.

At a reverse position R3 of the crusher valve 15 are disposed "P, A2connection with the flow rate control mechanism PQ", "P1, B1, B2connection", the check valve 15e for flowing from a direction of A1 to adirection of B2, and "A1, T1 connection with the flow rate controlmechanism PQ,". The connection position of each port of a neutralposition S3 and a forward position F3 is the same as the neutralposition S1 and the case opening position 01 of the crusher caseopening/closing valve 12. Thus, the description is omitted.

In FIG. 7, the pressure compensation valve 11 has the same structure asin FIG. 4. Since the same components have the same reference numbers,the description is omitted.

The feeder valve 16 is the same eight-port and three-position springcenter pilot operated type switch valve as the left traveling valve 13and the right traveling valve 14. However, since the flow rate controlmechanisms PQ differ between a forward position F4 and a reverseposition R4, this will be described in detail with reference to FIGS. 8,9A and 9B.

In the ports of the feeder valve 16 shown in FIG. 8, the same parts havethe same reference numbers as in FIG. 7. Thus, the description isomitted. A flow control valve 11g and a piston 11j with a throttle 11hare slidably inserted in a predetermined position of a valve body 16g inthe flow rate regulating valve 11a. The oil is sealed by a plug 11n atone end. Numeral 11k denotes a pressure chamber of the piston 11j. Thereducing valve 11b comprises a plunger 11t with a notch 11m, a pressurecontrolling spring 11x, and an interior piston 11y. The plunger 11t isslidably inserted in a predetermined position of the valve body 16g sothat it can be in contact with the flow control valve 11g. The oil issealed by the plug 11n at the other end. A spool 16h is held at aneutral position S4 about the pump port P by springs 16k and 16k, whichare inserted in the respective hydraulic chambers PA1 and PB1 disposedat both ends thereof.

FIG. 9A is an enlarged view of a portion Z showing the flow rate controlmechanism PQ portion of the spool 16h. A parallel notch portion 16w,which is parallel to a spool outer circumference having the diameter16u, is disposed in one part of a notch 16t, having a tapered shape 16s,for flowing a predetermined flow rate proportional to an opening area ofthe spool 16h in accordance with a required flow rate of the hydraulicmotor 29a for the feeder 29. The spool 16h is moved from its neutralposition S4, which is the center of the pump port P, toward the forwardposition F4 as shown by an arrow.

FIG. 9B shows a relationship between an amount of movement st of thespool 16h and a flow rate QF of the spool flowing in the flow ratecontrol mechanism PQ at that time. As the amount of the movement st ofthe spool 16h is increased from st1 to st2, the flow rate QF of thespool is increased from QF0 to QF1. When the amount of movement streaches st2, the flow rate QF of the spool becomes constant QF1. Thefeeder 29 is actuated at a set value speed V1. When the amount ofmovement st exceeds st3, the flow rate QF of the spool is increasedagain. When the amount of movement st reaches st4, the flow rate QF ofthe spool becomes the maximum flow rate QF2. The feeder 29 is actuatedat a rated speed V2.

Since the other discharge conveyor valve 17, the magnetic separatorvalve 18, the vibrating screen valve 19, the secondary loading conveyorvalve 20, and the secondary stock conveyor valve 21 have the samestructure as the feeder valve 16, the description is omitted.

Next, an overload preventing circuit of the transportable crusherdisposed in the controller 41 will be described with reference to FIG.10.

In the controller 41 are disposed a setter 50, for setting andoutputting an equivalent load level to the signals from the sensorsLS15, LS16F, LS16R, LS17, LS18, LS19, LS20, and LS21; an OR gate 51, forproviding the output signal when a signal is inputted from any sensor;AND gates 52, 53, and 54, which are comparators; and an output circuit55 for outputting the signal P16ae controlling the EPC valve P16a forforwardly rotating the feeder.

The setter 50 includes three kinds of circuits, that is, a first setsignal circuit 50a, a second set signal circuit 50b, and a third setsignal circuit 50c, for outputting a set signal which is preset when thesignal is the set equivalent load level or higher.

The output circuit 55 includes a start control circuit S1 for startingthe hydraulic motor 29a for the feeder by controlling the EPC valve P16afor forwardly rotating the feeder, an acceleration/deceleration controlcircuit S2 for accelerating/decelerating the hydraulic motor 29a for thefeeder in the same manner, and a set value speed/stop control circuit S3for operating at the set value speed or stopping the hydraulic motor 29afor the feeder in the same manner so as to output the signal P16ae.

When a signal from at least one of the sensors LS15, LS16F, LS16R, LS17,LS18, LS19, LS20, and LS21 is the set load pressure or higher, thesignal is inputted to the OR gate 51.

When the output signal of the OR gate 51 and the signal of the first setsignal circuit 50a are inputted to the AND gate 52, the AND gate 52outputs signals to the AND gate 53 and the start control circuit S1. TheEPC valve P16a, for forwardly rotating the feeder, switches the feedervalve 16 to the forward position F4 by the proportional current signalP16ae outputted from the start control circuit S1. The hydraulic motor29a for the feeder is started.

When the output signal of the AND gate 52 and the signal of the secondset signal circuit 50b are inputted to the AND gate 53, the AND gate 53outputs signals to the AND gate 54 and the acceleration/decelerationcontrol circuit S2. The EPC valve P16a, for forwardly rotating thefeeder moves the feeder valve 16 within the forward position F4responsive to the proportional current signal P16ae outputted from theacceleration/deceleration control circuit S2. The hydraulic motor 29afor the feeder is accelerated/decelerated.

When the output signal of the AND gate 53 and the signal of the thirdset signal circuit 50c are inputted to the AND gate 54, the AND gate 54outputs a signal to the set value speed/stop control circuit S3. The EPCvalve P16a, for forwardly rotating the feeder moves the feeder valve 16responsive to the proportional current signal P16ae, outputted from theset value speed/stop control circuit S3, so as to operate the hydraulicmotor 29a for the feeder at the set value speed. Alternatively, the EPCvalve P16a, for forwardly rotating the feeder, switches the feeder valve16 to the neutral position S4 so as to stop the hydraulic motor 29a forthe feeder.

Next, a traveling interlock circuit of the discharge conveyor 17disposed in the controller 41 will be described with reference to theflow chart of FIG. 11.

The signal from the limit switch 43, which is turned ON/OFF depending onthe upper position 42b or the lower position 42a of the dischargeconveyor 30, is determined in a step S10. When the discharge conveyor 30is positioned at the lower position 42a, YES is determined so that theoperation proceeds to a step S11. The output signal P8e of thecontroller 41 is turned OFF so that the transportable crusher cannottravel.

When the discharge conveyor 30 is positioned at the upper position 42b,NO is determined so that the operation proceeds to steps S12, S13 andS14. That is, since the limit switch 43 is turned ON in the step S12,the alarm 46 blares. The rotating light 45 is activated in the samemanner in the step S13. In the step S14, the signals P15ae, P15be,P16ae, P16be, P17e, P18e, P19e, P20e, and P21e are turned OFF from thecontroller 51 so as to stop the operation of each device.

FIG. 12 is a characteristics diagram of the feeder valve 16, showing theflow rate QF of the spool of the feeder valve 16 on an ordinate axis andshowing a current value iE of each solenoid proportional reducing valvewhich is the EPC valve P16a for forwardly rotating the feeder and theEPC valve 16b for reversely rotating the feeder on an abscissa axis.

As the current value iE is increased from iE to iE2, the flow rate QF ofthe spool is increased in proportion to the increase of the currentvalue iE. When the current value iE reaches iE2, the flow rate QF of thespool becomes the constant flow rate QF1. The feeder 29 is actuated atthe set value speed V1. When the current value iE is increased exceedingiE3, the flow rate QF of the spool is increased in proportion to thisincrease. When the current value iE reaches iE4, the flow rate QF of thespool becomes the maximum flow rate QF2. The feeder 29 is actuated atthe rated speed V2.

FIGS. 13A and 13B are instruction tables classified by two kinds offeeders, showing the current value iE of the feeder valve 16 on theordinate axis and showing a dial voltage Vp set by the speed setter 49of the feeder 29 on the abscissa axis. FIG. 13A shows a current patternA for the plate feeder. FIG. 13B shows a current pattern B for thegrizzly vibrating feeder. The instruction tables classified by these twokinds of feeders are stored in the controller 41. The operation of thefeeder identification switch 56 shown in FIG. 2 is selected, and therebyeach table can be read.

Next, the operation of the control circuit of the transportable crusherwill be described with reference to FIG. 3.

When the transportable crusher is traveled, the remote controller 41b isoperated so as to stop all the operating devices, that is, the crusher28, the feeder 29, the discharge conveyor 30, the magnetic separator 31,the vibrating screen 32, the secondary loading conveyor 33 and thesecondary stock conveyor 34. A rubber hose (not shown), connected to thevibrating screen 32, the secondary loading conveyor 33, and the asecondary stock conveyor 34, is cut off in a coupler section. Next, whenthe discharge conveyor 30 is stored in the upper position 42b, thepreparation for the traveling is completed.

During the traveling of the transportable crusher, the amount ofdischarge Qp is supplied from the hydraulic pump 1 to the hydraulicmotors 26a and 27a of the left and right traveling sections 26 and 27.Assume that the left and right traveling PPC valves P13 and P14 areoperated to their position F2 so that they are advanced. The loadpressure PLP of the left traveling section 26 is lower than that of theright traveling section 27, and the amount of discharge Qp is about toflow into the left traveling section 26. In this case, the pressurecompensation valves 11 reduce to the same pressure as the load pressurePLP so that the differential pressure can be the same in the flow ratecontrol mechanisms PQ between the inlet pump port P and the outletcontrol port A1 of the left and right traveling PPC valves P13 and P14.The compensation valves 11 compensate for the other pressurecompensation valves 11 as the LS pressure in accordance with the load,while acting on the hydraulic pump 1 as the LS pressure PLS.

As a result, the amount of discharge Qp of the hydraulic pump 1 isdistributed in proportion to an amount of operation of the lefttraveling valve 13 and the right traveling valve 14. Therefore, anadvancement operation is facilitated without individually disposing aplurality of pumps. When the left and right traveling PPC valves P13 andP14 are operated to their position R2 so as to move backwardly, theoperation is facilitated in the same manner as the advancement.

During the crushing operation of the transportable crusher by eachoperating device, in order to drive the actuator 25a, the hydraulicmotor 28a for the crusher 28, the hydraulic motor 29a for the feeder 29,the hydraulic motor 30a for rotating the discharge conveyor 30, thehydraulic motor 31a for rotating the magnetic separator 31, thehydraulic motor 32a for rotating the vibrating screen 32, the hydraulicmotor 33a for rotating the secondary loading conveyor 33, and thehydraulic motor 34a for rotating the secondary stock conveyor 34, eachhaving a different required power, the hydraulic pump 1 supplies theamount of discharge Qp in parallel to them.

As is the case with the left and right traveling sections 26 and 27, thepressure compensation valves 11 reduce to the same pressure as the loadpressure PLP so that the differential pressure can become the same inthe flow rate control mechanisms PQ between the inlet pump port P andthe outlet control port A1 or B2 of the closed-center type switch valves12, 15, 16, 17, 18, 19, 20, and 21 for independently controlling theamount of discharge Qp to the hydraulic motors and actuators. Thepressure compensation valves 11 compensate for the other pressurecompensation valves 11 as the LS pressure in accordance with the load,while fetching the top pressure generated in the load pressure circuitLS12 and controlling as the LS pressure PLS.

This LS pressure PLS acts on the LS valve 5. The LS valve 5 is balancedso that the differential pressure between the hydraulic pressure Pp ofthe hydraulic pump 1 and the LS pressure PLS can be always constant.

As a result, the hydraulic pump 1 supplies the amount of discharge Qp sothat the flow rate can be distributed in accordance with the amount ofoperation of the switch valves 12, 15, 16, 17, 18, 19, 20, and 21.Therefore, the hydraulic pump 1 is not required to be divided intoseveral pumps for the crusher 28 and for the other operating devices.The single variable displacement hydraulic pump 1, having the amount ofdischarge Qp in accordance with the total required power, can bedisposed. Accordingly, the pressurized oil, to be relieved from therelief valve 10 to the tank 22 for holding the pressure, is minimized bythe pump control. This results in less heat generation in the hydraulicfluid in the tank 22.

This control circuit is not specifically limited to the single largedisplacement hydraulic pump 1. A plurality of small displacementhydraulic pumps can be attached so as to use the joined discharge flowrate. In this case, a large fixed displacement pump and a complicateddistribution circuit are not disposed. Accordingly, a power loss of thepump can be reduced, and an overheating of the hydraulic fluid can beprevented.

The switch valves 12, 15, 16, 17, 18, 19, 20, and 21 distribute theamount of discharge Qp of the hydraulic pump 1 to the hydraulic motorsand actuators 25a, 26a, 27a, 28a, 29a, 30a, 31a, 32a, 33a, and 34a inaccordance with the amount of operation (opening area), not depending onthe size of the load of the hydraulic motors and actuators. Thus, thecrusher 28 driven by the large displacement hydraulic motor 28a, isactuated at a predetermined speed, even if the load of the hydraulicmotor 28a is varied.

The feeder 29, the discharge conveyor 30, etc., or the like is actuatedat a predetermined speed in the same manner, even if the loads of thehydraulic motors 29a and 30a are varied. As a result, the crusher 28crushes the objects to be crushed at a constant speed and delivers thecrushed objects to the discharge conveyor 30. Accordingly, the crushingefficiency is not reduced. Fewer emergency stops are caused due to theoverloading of the crusher 28 and the discharge conveyor 30.

The crusher valve 15 and the feeder valve 16 are provided with the EPCvalve P15a for forwardly rotating the crusher, the EPC valve P15b forreversely rotating the crusher, the EPC valve P16a for forwardlyrotating the feeder, and the EPC valve 16b for reversely rotating thefeeder, which are the solenoid proportional reducing valves fordistributing the amount of discharge Qpa of the controlling hydraulicpump 2. Thus, when the crusher 28 crushes the objects to be crushedwhich have been introduced into the hopper 35, if the hydraulic motor28a, 29a, or 30a of the feeder 29, the crusher 28, or the dischargeconveyor 30 is overloaded, the amount of discharge Qp of the hydraulicpump 1 is distributed in the order of, for example, the crusher 28, thedischarge conveyor 30, and the feeder 29 in accordance with apredetermined order of priority.

Consequently, the controller 41 instructs the feeder 29 to stop thedelivery to the crusher 28 of the objects to be crushed. Next, thecontroller 41 gives the instruction to stop the discharge conveyor 30after a predetermined time interval so as to stop the discharge conveyor30. Within a predetermined time interval, the crusher 28 crushes theobjects to be crushed in the crusher 28 and then discharges the crushedobjects to the discharge conveyor 30. Finally, the controller 41 givesthe instruction to stop the crusher 28 so that the crusher 28 isstopped. Thus, the crushed objects are not jammed into the crusher 28and do not remain on the discharge conveyor 30. Accordingly, the checkand maintenance work are facilitated. The overload is solved, therebyfacilitating the automatic restoration of the controller 41.

When the feeder valve 16 is operated in order to start the feeder 29, asshown in FIGS. 9A and 9B, even if the amount of movement st of the spoolis increased to expose more of the parallel notch portion 16w, which isparallel to the spool outer circumference represented by diameter 16u,in the notch 16t disposed in the spool 16h, the flow rate QF of thespool becomes constant. That is, the hydraulic motor 29a is actuated atthe set value speed V1. The portion having the set value speed V1 isdisposed, thereby allowing the feeder 29 to be easily actuated in eachspeed stage of the set value speed V1 and the rated speed V2. That is,the feeder 16 has characteristics allowing the feeder 29 to be actuatedat the set value speed V1 and the rated speed V2 by the instruction fromthe controller 41.

The controller 41 can also select, with a dial by the speed setter 49,the first speed control for starting, accelerating/decelerating, andstopping the feeder 29 and the second speed control for starting,accelerating/decelerating, and operating at the set value speed thefeeder 29. The feeder identification switch 56 is operated so as toselect the instruction tables classified by the feeder type. Thus, it ispossible to control the speed classified by two kind of feeders by thecurrent pattern A for the plate feeder that is the first speed controland the current pattern B for the grizzly vibrating feeder that is thesecond speed control.

As a result, when the current pattern A is used for the plate feeder,the speed control of the plate feeder can be performed in proportion tothe range from the stop to the rated speed.

Not only when the current pattern B is used for the grizzly vibratingfeeder but also when it is used for the vibrating feeder having aresonant point at a low speed just before the stop, the set value speedoperation is performed prior to the resonance of the vibrating feeder.After the reduction of the load of the crusher 28 and the dischargeconveyor 30, the automatic restoration for accelerating the vibratingfeeder to the rated speed is performed prior to the resonance of thevibrating feeder. After the reduction of the load of the crusher 28 andthe discharge conveyor 30, the automatic restoration for acceleratingthe vibrating feeder to the rated speed is facilitated. Accordingly, thecrushing efficiency is improved.

Even if the hydraulic motors for the plate feeder and for the vibratingfeeder have different performances, the same hydraulic pump 1 and theswitch valves of the operating valve assembly 8 can be used. Therefore,the assembly is facilitated.

When the discharge conveyor 30 is positioned at the lower position 42a,the limit switch 43, for turning ON/OFF the power source circuit 44, isturned OFF. The controller 41 turns OFF the instruction signal P8e so asto switch the traveling interlock solenoid valve P8. The pilot oil pathP9 is connected to the tank 22. The amount of discharge Qpa of thehydraulic pump 2 is interrupted. Thus, the transportable crusher cannottravel. Accordingly, if the operator should inadvertently press atraveling lever of the transportable crusher during the crushingoperation, the transportable crusher does not travel, thereby allowingsafety to be ensured.

INDUSTRIAL APPLICABILITY

The present invention is useful as a control circuit of a transportablecrusher which supplies, by the same pump, a required flow rate tohydraulic motors and actuators for a plurality of operating deviceshaving different loads, improves simultaneous operability, fineadjustment, and reproducibility, prevents an overload of each device bysetting an order of priority of operation/stop of plural operatingdevices, and has excellent safety during the traveling of thetransportable crusher.

What is claimed is:
 1. A control circuit for a transportable crusherhaving a plurality of hydraulic units for a plurality of operatingdevices having different loads during a crushing operation, wherein eachhydraulic unit is selected from the group consisting of hydraulic motorsand hydraulic actuators, said control circuit comprising:at least onevariable displacement hydraulic pump, for supplying a single dischargeflow of hydraulic fluid; a plurality of switch valves, each of saidplurality of switch valves being for conducting and interrupting flow ofhydraulic fluid from said at least one variable displacement hydraulicpump to a respective one of said hydraulic units; a plurality ofpressure compensation control valves, each of said plurality of pressurecompensation control valves inputting a front pressure and a backpressure of a respective one of said switch valves for controlling adischarge flow rate of said single discharge flow from said at least onevariable displacement hydraulic pump so that a difference between arespective front pressure and a corresponding back pressure can becomeconstant; and a controller for controlling each of said switch valves toa predetermined value set in accordance with a load of said hydraulicunits and for controlling said switch valves, when at least some of saidswitch valves are simultaneously operated and at least one of saidhydraulic units is overloaded, to distribute said discharge flow rateamong said switch valves in accordance with a predetermined priority. 2.A control circuit in accordance with claim 1, wherein one of saidplurality of operating devices is a feeder, and wherein one of saidhydraulic units is a feeder hydraulic motor for operating the feeder;said control circuit further comprising:a feeder valve for controlling aspeed of said feeder, said feeder valve having a spool which includes atapered notch for flowing a flow rate proportional to an opening area ofsaid spool in accordance with a flow rate required by the feederhydraulic motor, said tapered notch including a parallel notch portionwhich is parallel to an outer circumference of the spool for allowingthe flow rate through the feeder valve to be constant even if an amountof movement of said spool is increased to expose more of the parallelnotch portion.
 3. A control circuit in accordance with claim 1, whereinone of said plurality of operating devices is a feeder; wherein saidplurality of hydraulic units includes a plurality of hydraulic motors,each of said hydraulic motors being for driving a respective one of saidplurality of operating devices; and wherein said controller comprises:asetter for presetting a load of said feeder; a plurality of detectors,each of said detectors being for detecting a load of a hydraulic motorfor driving a respective one of said plurality of operating devices; aplurality of comparators, each of said comparators being for comparingsignals inputted from said detectors to an equivalent load level towhich said setter presets the load of said feeder; a solenoidproportional reducing valve for said feeder; and an output circuit foroutputting an instruction signal to said solenoid proportional reducingvalve of said feeder in response to output signals of said comparatorsand for controlling a speed of said feeder.
 4. A control circuit inaccordance with claim 3, wherein one of said hydraulic motors is afeeder hydraulic motor for operating the feeder; said control circuitfurther comprising:an identification switch; and wherein said controllercomprises:a current pattern A of a first speed control for starting,accelerating/decelerating, and stopping said feeder hydraulic motor; anda current pattern B of a second speed control for starting,accelerating/decelerating, and operating said feeder hydraulic motor ata set value speed; and wherein said controller gives an instruction tosaid solenoid proportional reducing valve in accordance with one of saidcurrent patterns selected by said identification switch so as to controla speed of said feeder.
 5. A control circuit in accordance with claim 4,wherein one of said plurality of operating devices is a dischargeconveyer; and further comprising:a position sensor for detecting astoring position of said discharge conveyer, said position sensor beingconnected to said controller through a power source circuit, whereinsaid position sensor is turned OFF when said discharge conveyer ispositioned at a position for a crushing operation; and a travelinginterlock solenoid valve, wherein a signal from said controller to saidtraveling interlock solenoid valve is turned OFF when said dischargeconveyer is positioned at a position for a crushing operation, so that atraveling of said transportable crusher is prevented.
 6. A controlcircuit in accordance with claim 5, further comprising a rotating lightand an alarm; andwherein said position sensor is connected to saidrotating light and said alarm; and wherein said position sensor isturned ON when said discharge conveyer is positioned at said storingposition during a stop of a crushing operation so that said rotatinglight and said alarm are actuated to provide a display of a traveling ofsaid transportable crusher.
 7. A control circuit in accordance withclaim 6, further comprising:a feeder valve for controlling a speed ofsaid feeder, said feeder valve having a spool which includes a taperednotch for flowing a flow rate proportional to an opening area of saidspool in accordance with a flow rate required by the feeder hydraulicmotor, said tapered notch including a parallel notch portion which isparallel to an outer circumference of the spool for allowing the flowrate through the feeder valve to be constant even if an amount ofmovement of said spool is increased to expose more of the parallel notchportion.
 8. A control circuit in accordance with claim 1, wherein one ofsaid plurality of operating devices is a discharge conveyer; and furthercomprising:a position sensor for detecting a storing position of saiddischarge conveyer, said position sensor being connected to saidcontroller through a power source circuit, wherein said position sensoris turned OFF when said discharge conveyer is positioned at a positionfor a crushing operation; and a traveling interlock solenoid valve,wherein a signal from said controller to said traveling interlocksolenoid valve is turned OFF when said discharge conveyer is positionedat a position for a crushing operation, so that a traveling of saidtransportable crusher is prevented.
 9. A control circuit in accordancewith claim 8, further comprising a rotating light and an alarm;andwherein said position sensor is connected to said rotating light andsaid alarm; and wherein said position sensor is turned ON when saiddischarge conveyer is positioned at said storing position during a stopof a crushing operation so that said rotating light and said alarm areactuated to provide a display of a traveling of said transportablecrusher.
 10. A control circuit in accordance with claim 1, wherein oneof said plurality of operating devices is a feeder, and wherein one ofsaid hydraulic units is a feeder hydraulic motor for operating thefeeder; said control circuit further comprising:an identificationswitch; and wherein said controller comprises:a current pattern A of afirst speed control for starting, accelerating/decelerating, andstopping said feeder hydraulic motor; and a current pattern B of asecond speed control for starting, accelerating/decelerating, andoperating said feeder hydraulic motor at a set value speed; and whereinsaid controller gives an instruction to operate said feeder hydraulicmotor in accordance with one of said current patterns selected by saididentification switch so as to control a speed of said feeder.
 11. Acontrol circuit in accordance with claim 1, wherein one of saidplurality of operating devices is a discharge conveyer; and furthercomprising:a position sensor for detecting a storing position of saiddischarge conveyer; and a traveling interlock solenoid valve, whereinsaid controller provides a signal to said traveling interlock solenoidvalve so that a traveling of said transportable crusher is preventedwhen said position sensor detects that said discharge conveyer is not insaid storing position.
 12. A control circuit in accordance with claim 1,wherein one of said plurality of operating devices is a dischargeconveyer; and further comprising:an indicator; and a position sensor fordetecting a storing position of said discharge conveyer, said positionsensor being connected to said indicator so that said indicator can beactuated to provide a display of a traveling of said transportablecrusher when said position sensor detects that said discharge conveyeris positioned at said storing position.
 13. A control circuit inaccordance with claim 1, wherein said at least one variable displacementhydraulic pump is a single variable displacement hydraulic pump.
 14. Acontrol circuit in accordance with claim 1, wherein said transportablecrusher comprises a crusher, a feeder, and a discharge conveyor, whereinsaid plurality of hydraulic units include a hydraulic motor for drivingsaid crusher, a hydraulic motor for driving said feeder, and a hydraulicmotor for driving said discharge conveyor, and wherein distributing saiddischarge flow rate in accordance with said predetermined prioritycomprises distributing said discharge flow rate in the order of saidcrusher, said discharge conveyor, and said feeder.
 15. A control circuitin accordance with claim 14, wherein, when one of said hydraulic unitsbecomes overloaded, said controller stops said feeder, and then after apredetermined time interval stops said discharge conveyor and saidcrusher, wherein said predetermined time interval is sufficient for saidcrusher to crush objects within said crusher to be crushed and todeposit resulting crushed material on said discharge conveyor.
 16. Atransportable crusher comprising:a plurality of operating devices havingdifferent loads during a crushing operation; a plurality of hydraulicunits for operating said plurality of operating devices during acrushing operation, wherein each hydraulic unit is selected from thegroup consisting of hydraulic motors and hydraulic actuators; at leastone variable displacement hydraulic pump, for supplying a singledischarge flow of hydraulic fluid; a plurality of switch valves, each ofsaid plurality of switch valves being for conducting and interruptingflow of hydraulic fluid from said at least one variable displacementhydraulic pump to a respective one of said hydraulic units; a pluralityof pressure compensation control valves, each of said plurality ofpressure compensation control valves inputting a front pressure and aback pressure of a respective one of said switch valves for controllinga discharge flow rate of said single discharge flow from said at leastone variable displacement hydraulic pump so that a difference between arespective front pressure and a corresponding back pressure can becomeconstant; and a controller for controlling each of said switch valves toa predetermined value set in accordance with a load of said hydraulicunits, and for controlling said switch valves, when at least some ofsaid switch valves are simultaneously operated and at least one of saidhydraulic units is overloaded, to distribute said discharge flow rateamong said switch valves in accordance with a predetermined priority.17. A transportable crusher in accordance with claim 16, wherein one ofsaid plurality of operating devices is a feeder, and wherein one of saidhydraulic units is a feeder hydraulic motor for operating the feeder;said transportable crusher further comprising:a feeder valve forcontrolling a speed of said feeder, said feeder valve having a spoolwhich includes a tapered notch for flowing a flow rate proportional toan opening area of said spool in accordance with a flow rate required bythe feeder hydraulic motor, said tapered notch including a parallelnotch portion which is parallel to an outer circumference of the spoolfor allowing the flow rate through the feeder valve to be constant evenif an amount of movement of said spool is increased to expose more ofthe parallel notch portion.
 18. A transportable crusher in accordancewith claim 16, wherein one of said plurality of operating devices is afeeder; wherein said plurality of hydraulic units includes a pluralityof hydraulic motors, each of said hydraulic motors being for driving arespective one of said plurality of operating devices, and wherein saidcontroller comprises:a setter for presetting a load of said feeder; aplurality of detectors, each of said detectors being for detecting aload of a hydraulic motor for driving a respective one of said pluralityof operating devices; a plurality of comparators, each of saidcomparators being for comparing signals inputted from said detectors toan equivalent load level to which said setter presets the load of saidfeeder; a solenoid proportional reducing valve for said feeder; and anoutput circuit for outputting an instruction signal to said solenoidproportional reducing valve of said feeder in response to output signalsof said comparators and for controlling a speed of said feeder.
 19. Atransportable crusher in accordance with claim 18, wherein one of saidhydraulic motors is a feeder hydraulic motor for operating the feeder;said transportable crusher further comprising:an identification switch;and wherein said controller comprises:a current pattern A of a firstspeed control for starting, accelerating/decelerating, and stopping saidfeeder hydraulic motor; and a current pattern B of a second speedcontrol for starting, accelerating/decelerating, and operating saidfeeder hydraulic motor at a set value speed; and wherein said controllergives an instruction to said solenoid proportional reducing valve inaccordance with one of said current patterns selected by saididentification switch so as to control a speed of said feeder.
 20. Atransportable crusher in accordance with claim 19, wherein one of saidplurality of operating devices is a discharge conveyer; and furthercomprising:a position sensor for detecting a storing position of saiddischarge conveyer, said position sensor being connected to saidcontroller through a power source circuit, wherein said position sensoris turned OFF when said discharge conveyer is positioned at a positionfor a crushing operation; and a traveling interlock solenoid valve,wherein a signal from said controller to said traveling interlocksolenoid valve is turned OFF when said discharge conveyer is positionedat a position for a crushing operation, so that a traveling of saidtransportable crusher is prevented.
 21. A transportable crusher inaccordance with claim 20, further comprising a rotating light and analarm; andwherein said position sensor is connected to said rotatinglight and said alarm; and wherein said position sensor is turned ON whensaid discharge conveyer is positioned at said storing position during astop of a crushing operation so that said rotating light and said alarmare actuated to provide a display of a traveling of said transportablecrusher.
 22. A transportable crusher in accordance with claim 21,wherein one of said hydraulic motors is a feeder hydraulic motor foroperating the feeder, said transportable crusher further comprising:afeeder valve for controlling a speed of said feeder, said feeder valvehaving a spool which includes a tapered notch for flowing a flow rateproportional to an opening area of said spool in accordance with a flowrate required by the feeder hydraulic motor, said tapered notchincluding a parallel notch portion which is parallel to an outercircumference of the spool for allowing the flow rate through the feedervalve to be constant even if an amount of movement of said spool isincreased to expose more of the parallel notch portion.
 23. Atransportable crusher in accordance with claim 16, wherein one of saidplurality of operating devices is a discharge conveyer; and furthercomprising:a position sensor for detecting a storing position of saiddischarge conveyer, said position sensor being connected to saidcontroller through a power source circuit, wherein said position sensoris turned OFF when said discharge conveyer is positioned at a positionfor a crushing operation; and a traveling interlock solenoid valve,wherein a signal from said controller to said traveling interlocksolenoid valve is turned OFF when said discharge conveyer is positionedat a position for a crushing operation, so that a traveling of saidtransportable crusher is prevented.
 24. A transportable crusher inaccordance with claim 23, further comprising a rotating light and analarm; andwherein said position sensor is connected to said rotatinglight and said alarm; and wherein said position sensor is turned ON whensaid discharge conveyer is positioned at storing position during a stopof a crushing operation so that said rotating light and said alarm areactuated to provide a display of a traveling of said transportablecrusher.
 25. A transportable crusher in accordance with claim 16,wherein one of said plurality of operating devices is a feeder, andwherein one of said hydraulic units is a feeder hydraulic motor foroperating the feeder; said transportable crusher further comprising:anidentification switch; and wherein said controller comprises:a currentpattern A of a first speed control for starting,accelerating/decelerating, and stopping said feeder hydraulic motor; anda current pattern B of a second speed control for starting,accelerating/decelerating, and operating said feeder hydraulic motor ata set value speed; and wherein said controller gives an instruction tooperate said feeder hydraulic motor in accordance with one of saidcurrent patterns selected by said identification switch so as to controla speed of said feeder.
 26. A transportable crusher in accordance withclaim 16, wherein one of said plurality of operating devices is adischarge conveyer; and further comprising:a position sensor fordetecting a storing position of said discharge conveyer; and a travelinginterlock solenoid valve, wherein said controller provides a signal tosaid traveling interlock solenoid valve so that a traveling of saidtransportable crusher is prevented when said position sensor detectsthat said discharge conveyer is not in said storing position.
 27. Acontrol circuit in accordance with claim 16, wherein one of saidplurality of operating devices is a discharge conveyer; and furthercomprising:an indicator; and a position sensor for detecting a storingposition of said discharge conveyer, said position sensor beingconnected to said indicator so that said indicator can be actuated toprovide a display of a traveling of said transportable crusher when saidposition sensor detects that said discharge conveyer is positioned atsaid storing position.
 28. A transportable crusher in accordance withclaim 16, wherein said at least one variable displacement hydraulic pumpis a single variable displacement hydraulic pump.
 29. A transportablecrusher in accordance with claim 16, wherein said transportable crushercomprises a crusher, a feeder, and a discharge conveyor, wherein saidplurality of hydraulic units includes a hydraulic motor for driving saidcrusher, a hydraulic motor for driving said feeder, and a hydraulicmotor for driving said discharge conveyor, and wherein distributing saiddischarge flow rate in accordance with said predetermined prioritycomprises distributing said discharge flow rate in the order of saidcrusher, said discharge conveyor, and said feeder.
 30. A transportablecrusher in accordance with claim 29, wherein, when one of said hydraulicunits becomes overloaded, said controller stops said feeder, and thenafter a predetermined time interval stops said discharge conveyor andsaid crusher, wherein said predetermined time interval is sufficient forsaid crusher to crush objects within said crusher to be crushed and todeposit resulting crushed material on said discharge conveyor.